Chapter 14 Flashcards
The diversity of life is evolved through
Speciation
The process in which one species splits into two or more species
Speciation
_____ is a Latin word meaning kind or appearance
Species
Defines a species as a group of “populations whose members have the potential to interbreed with one another and produce fertile offspring (offspring that can reproduce)”
Biological species concept
populations whose members have the potential to interbreed with one another and produce fertile offspring (offspring that can reproduce)
Species
- measurable physical traits
- molecular data
- small group of individuals sharing a common ancestor
How Biologists define species
Things that prevent closely related species from breeding
Reproductive barriers
This is in place so members of different species cannot successfully reproduce (have high fitness)
Reproductive barriers
- temporal isolation
- habitat isolation
- behavioral isolation
Prezygotic barriers
- mechanical isolation
- gamete isolation
Mating attempt
To prevent mating or fertilization between species
Prezygotic barriers
Species that mate at different times
Temporal isolations
Species that are most likely not going to mate because of different habitats
Habitat isolation
Mating or fertilization occurs at different seasons or times of day
Temporal isolation
Little or no sexual attraction exist between populations. Such as odor, coloration, or courtship ritual, can also function as reproductive barriers
Behavioral isolation
Structural differences prevent fertilization. The egg producing and sperm producing parts of different species are anatomically incompatible
Mechanical isolation
Female and make gametes fail to untie in fertilization. (Don’t fuse)
Gametic isolation
This operates if interspecies mating occurs in hybrid zygotes form
Postzygotic Barriers
Hybrid zygotes fail to develop or failed to reach sexual maturity
Reduced Hybrid Viability
Hybrids failed to produce functional gametes
Reduced Hybrid Fertility
Hybrids are feeble or sterile. Different species of cotton plants can produce fertile hybrids, but the offspring of the hybrids do not survive.
Hybrid breakdown
A key event in the origin of a species occurs when a ___ from other populations of the ___
Population is somehow cut off; parent species
In which the initial block to gene pool is a geographic barrier that physically isolate the splinter population
Allopatric speciation
The origin of new species without geographic isolation
Sympatric speciation
“Different country”
Allopatric speciation
“Same country”
Sympatric speciation
This process can fragment a population into two or more isolated populations and contribute to all allopatric speciation
Geologic processes
Speciation occurs with the evolution of reproductive barriers between the isolated population and its parent population
Allopatric Speciation
Even if the two populations should come back into contact at some later time, ____
The reproductive barriers will keep them as separate species
In allopatric speciation occurs with the evolution of reproductive barriers between ____ and ____
Isolated population and it’s parent population
A species may originate from an accident during cell division that results in an extra set of chromosomes
Polyploidy
Has been found in some animal species especially fish and amphibians, most common in plants
Polyploid speciation
Is most common in plants- majority of present day plant species are descended from ancestors that arose by
Polyploid speciation
Two distinct forms of polyploidy have been observed
- Polyploidy occurs leading to new species in overlapping geographic location
- Two different species might interbreed and produce hybrid offspring
Oats Potatoes Bananas Strawberries Peanuts Apples Sugarcane Wheat
Polyploids
One of the worlds greatest showcases of speciation
Galápagos Islands
Researchers have documented at least two dozen cases in which populations are currently diverging as they
- use different food resources or
- breed in different habitats
Much of the evidence for evolution comes from the
Fossil record
In one survey of 84 groups of plants and animals the time for __
Speciation ranges from 4,000 to 40 million years
Evolutionary change above the species level.
Includes the impact of mass extinctions on the diversity of life and it’s subsequent recovery
Macroevolution
An understanding of ____begins with a look at the span of geologic time over which life’s diversity has evolved
Macroevolution
The sequence in which fossils appear in rock strata and an archive of macroevolution
Fossil record
This divides earths history into a consistent sequence of geologic periods
Geologic time scale